1. Field of the Invention
The present invention relates a single-phase transparent aqueous liquid cosmetic composition comprising at least one metabisulfite and at least one alkyl para-hydroxybenzoate (paraben), and to the use of the composition for gently cleaning and/or removing make-up from the skin and/or eyes. Another subject-matter of the invention is a process for dissolving an alkyl para-hydroxybenzoate in an aqueous cosmetic composition by adding at least one metabisulfite thereto.
2. Discussion of the Background
Single-phase (monophase) transparent aqueous liquid compositions are compositions which do not comprise an oily phase and which constitute cleaning and make-up removal lotions. These lotions are commonly used in the cosmetics field, in particular for completing the removal of make-up from the skin and/or eyes after the use of a milk. They comprise a large amount of water and constitute, for example, toning lotions and make-up removers for the eyes.
These monophase aqueous liquid compositions comprise preservatives, in particular alkyl para-hydroxybenzoates, also known as parabens. These parabens, and in particular methylparaben, which are widely used in cosmetics for their antifungal properties, exhibit the disadvantage of having very little solubility in aqueous medium. In fact, if they are not entirely dissolved the parabens have a tendency to recrystallize, which is reflected by the formation of white particles. Such white particles have an unacceptable affect on the visual appearance and the sensorial quality of a transparent composition. In addition, in order to fully carry out their role of preservatives in the aqueous phase, the site of contamination, the parabens have to be completely dissolved in the aqueous phase.
It is therefore essential for the parabens to be entirely dissolved in the aqueous compositions, and in particular the transparent aqueous compositions, in order to achieve the greatest possible effectiveness and also in order to obtain perfect transparency of the composition.
One solution in promoting the solubilization of the parabens consists in adding a primary alcohol, such as ethanol, a polyol, such as a glycol, or a surfactant to the aqueous composition. However, the addition of primary alcohol is to be avoided, in particular in face lotions, because ethanol can have an irritating effect on skin. Furthermore, the addition of an excessively large amount of glycols confers a sticky and clinging nature on a liquid composition, such as a lotion. Moreover, the aim is to avoid the use of an excessively large amount of surfactants, due to their irritating nature with regard to the skin and eyes, in particular in sensitive subjects. In addition, some anionic and nonionic surfactants are incompatible with the parabens, the activity of which they inhibit.
The need therefore remains to have available a single-phase aqueous liquid cosmetic composition which does not have the disadvantages of known compositions and which is perfectly transparent by virtue of complete solubilization of the parabens.